The present invention relates to a bearing and, more particularly, to a spiral groove bearing (to be referred to as an SGB for brevity hereinafter).
The SGB is a dynamic pressure hydrodynamic bearing and has a plurality of parallel and shallow grooves which are tilted in the direction such that a lubricating fluid flows from an external portion to a predetermined portion when one of two surfaces opposing each other in a bearing portion is moved relative to the other, or when both are moved relative to each other. The bearing of this type has been recently used in a wide variety of applications.
However, in a conventional SGB, several drawbacks are encountered which are described in detail with reference to DETAILED DESCRIPTION OF THE PRIOR ART.